[!TIP] Patient (esp. Female) with abdominal pain + neuropsychiatric features -> need to consider acute porphyria.
Clinical features: Abdominal pain, neuropsychiatric features, seizures and fever.
Can be precipitated by anaesthetic drugs and luteal phase of the menstrual cycle.
Anaesthesia for suspected acute abdomen can be catastrophic.
The defective enzyme in acute intermittent porphyria is porphobilinogen deaminase.
The defect is in uroporphyrinogen decarboxylase.
80% of cases are acquired / sporadic; 20% are inherited.
Uroporphyrinogen decarboxylase converts uroporphyrinogen III into coproporphyrinogen III.
Presents with photosensitive blistering rash.
Hypertrichosis and hyperpigmentation may be present.
Liver disease is a common comorbidity:
Triggers for attacks are caused by increased hepatic iron load but also alcohol, smoking, estrogens, hepatitis C or HIV.
Phlebotomy - used to decrease the iron load.
Hydroxycholorquine - increase the excretion of porphyrins.
1. Overnight 1mg dexamethasone suppression test
Psoriatic arthritis is associated with HLA-B27.
Differentiation is clinically important because prognosis and management are different.
| PsA | RA |
|---|---|
| better prognosis | Somewhat worse |
| Early disease -> NSAIDS | DMARDs started early |
| Dactylitis, enthesistis, tenosynovitis | - |
| pattern: asymmetric oligo / symmetric, DIP is specific | Symmetric polyarthritis of PIP / MCP |
| Sacroiliitis | - |
| Nail changes | - |
| - | proximal hand and foot involvement (?wrist and ankles) |
| Source |
HMG-CoA reductase: Rate limiting enzyme in cholesterol sythesis : found in the liver and ? other tissues
LCAT : the enzyme synthesized by the liver and attached to HDL which exterifies cholesterol so that it becomes trapped inside HDL. Required for reverse transport of cholesterol.
LPL: lipoprotein lipase: the enzyme found on tissues which removes lipids from VLDL and it's derivatives, increasing their density.
If there is acidosis (pH < 7.2 or HCO3 < 15) or high ketonemia, manage as DKA.
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Endemic typhus serves as the prototype for pathogenesis:
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Interface hepatitis is seen, just like autoimmune hepatitis.
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Symptoms : N/V, headache,
motor effects: nystagmus, tremor, cerebellar ataxia.
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